Yep, the path to monetization is always adding new value-adds, not trying to charge for the current functionality after the fact.
Though I suppose some startups are genuinely naive enough to just launch and hope they'll find a revenue stream rich enough later.
I'm not saying they're right or wrong, but they believe so. You need to count this when writing down your monetization plan. People nowadays are generally extremely entitled.
It increased revenue and decreased costs from the tiny percentage that actually left. I think it’s win/win for any business that doesn’t rely on network effects.
At the very least you should grandfather in old users and only change it for new users going forward.
What did I do? Found a different job and employer. Jobs are like insurance rates: you should shop around occasionally. For businesses it's a cost of doing business when trying to compete to lure new workers.